The present invention relates to digital signal recording methods and disk reproducing apparatus, and more particularly to such method and device for recording a digital signal in the form of a data block on a disk and adapted to be accessed by a host computer and for reproducing the digital signal from the disk.
Conventionally, a CD-ROM (CD-Read Only Memory) is named as a disk on which digital signals are recorded in units of a data block of this type. Like the techniques described in "Nikkei Byte" September 1994, p. 146, in the CD-ROM, data blocks composed of effective data and its block address are recorded outward in order from the innermost track on the recording surface of the disk. When such disk on which such data is recorded, using the above technique, is accessed and reproduced in accordance with a command from the host computer, a start block address and a transfer block length are designated along with the access command, and a desired data block is accessed and reproduced in accordance with such command and data.
Recently, disks each composed of two subdisks stuck to each other whose recording surfaces are readable from one side, disks having an upper and a lower recording surface whose recording surfaces are readable from one side, and disks each composed of two stuck sets of upper and lower recording surfaces which are readable from one side have been standardized. Refer to for example, the headline "Confidence in Unique Standards of DVDS", Nikkei Sangyo Shinbun, Feb. 24, 1995, and the headline "Second Stage of Struggle for DVD Standards", Nihon Keizai Shinbun, Apr. 20, 1995.
When a digital signal is recorded, using the above-mentioned technique, on any of those disks having a plurality of recording surfaces, the host computer is only recognized as disks independent for the respective recording surfaces. In order to enable all the recording surfaces to be accessed, the interface via which data is sent/received to/from the host computer is required to be changed, and hence the conventional interface as it is cannot be used.
The above-mentioned techniques have the problem that each time a recording surface to be reproduced is changed to read the innermost lead-in area before access and reproduction, it takes much time to resume the access.